In the first line on this thread, this question was presented: "So where's the cooler temperatures?"
The word, 'temperatures', is plural. 'Where's' written out is--where is. Is implies the singular.
Therefore, the SENTENCE should read as follows: So where's the cooler temperature? OR Where are the cooler temperatures?
OR Why isn't it cooler?
Let's not correct others until our writing has exceeded that of a ninth grader.
"Be not like dumb, driven cattle. Be a hero in the strife." A Psalm of Life...Walt Whitman